It is known in the art to provide a two-stroke cycle air compressor having one or more cylinders driven by an internal combustion engine also having one or more cylinders. The compressor and engine cylinders may be formed within a common frame, or crankcase, and have pistons connected to a common crankshaft and the engine cylinders may be operated on either a two or four-stroke cycle.
In two-stroke cycle engines, the cylinders may be scavenged and charged by a separate blower or air pump. The engine cylinder charge may also be further compressed by an exhaust driven supercharger or turbocharger.
Two-stroke air compressors are not required to be scavenged by a separate air pump but it is known to provide two stage compression by arranging two compressor units or cylinders in series. Properly matched, such an arrangement will inherently increase the volumetric flow, or charging efficiency, of the second stage compressor cylinder.